Even after new tires, wheels, getting them balanced, getting the driveshaft balanced with a new joints and carrier baring installed.....I still have a slight vibration I can feel in the seat at around 65-70mph. Under that it's smooth as can be....over that it's smooth as can be. Any ideas as to what could be causing it? Ordinarily I wouldn't care....but it's right at the speed that I cruise down the highway at...so it's annoying. It's a very high frequency vibration....not really like an out of balance tire. More like a driveshaft type vibration....but I've already had that balanced with all new u-joints.

Are these trucks just prone to some odd resonance type vibrations at difference speeds?

 

Very common issue. The best way to solve it is to put in a 1 piece drive shaft.

 

When I had my driveshaft baanced, I asked the shop if they could make a 1 piece driveshaft for the truck....but they told me it was too long to make it a one piece shaft.

Is that vibration just a byproduct of a 2-piece drive shaft?

 

If your truck is a short bed then you can do a 1 piece drive shaft, if it is a long bed you are stuck with a 2 piece shaft. 2 major contributors to the vibration are the rear axle pinion deflection and the weak stock mount for the T-case. Those allow the drive shaft to move a lot in an elliptical rotation. A custom well built drive shaft will be better than the stock one you have now.

 

I know this may sound stupid, but it might be worth a try.

Get a hose clamp that will fit over the driveshaft. Put it on the back shaft and tighten it down. Go for a drive. Did the vibration change? (Not always better or worse, just changed).

If yes, the rear shaft may be the issue. If not, repeat ahead if the carrier bearing. Did the vibration change?

If again no, this might not be a driveshaft issue

 

My 2004 does the same thing for over five freaking years now! I have a short bed ext cab so it's a one piece shaft...new wheels tires shocks brakes driveshaft rebuilt new transmission mount you name it and it still wint go away! I've given up and just dont care any longer, I feel if something is wrong with the truck then it would gave failed after five years. So I just try and forget about it while driving